Debt, Financing Arrangements, and Leases (Details)				12 Months Ended
	Dec. 18, 2015	Feb. 02, 2015 USD ($)	Oct. 02, 2009	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Debt Instrument [Line Items]
Debt issuance costs				$ (1,197,000)	$ (1,932,000)
Unamortized debt discount				(383,000)	(580,000)
Total long-term debt, including current portion				693,420,000	692,488,000
Long-term debt due within one year				174,837,000	0
Total long-term debt				$ 518,583,000	692,488,000
7% senior unsecured notes				7.00%
Maturities of long-term debt
2016: 7% senior unsecured notes				$ 175,000,000
2017: 5.95% senior unsecured notes				185,000,000
2018: 6.05% senior unsecured notes				250,000,000
Total				610,000,000
Line of Credit Facility [Line Items]
Lease, initial term			10 years
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2016				2,561,000
2017				2,619,000
2018				2,679,000
2019				2,740,000
Total				10,599,000
Operating Leases, Rent Expense, Net [Abstract]
Operating lease rent expense, net of sublease revenues				2,700,000	2,500,000	$ 2,300,000
Minimum [Member]
Line of Credit Facility [Line Items]
Lease, renewal term			5 years
Maximum [Member]
Line of Credit Facility [Line Items]
Lease, renewal term			10 years
Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 3,500,000,000
Additional amount by which credit facility can be increased		500,000,000
Line of credit facility, remaining borrowing capacity		$ 500,000,000
Maximum Ratio Of Debt To Capitalization		65.00%
Commercial paper				499,000,000
Williams Partners L.P. [Member] | Rate addition to federal funds effective rate [Member]
Line of Credit Facility [Line Items]
Line of credit facility, basis spread on variable rate		0.50%
Williams Partners L.P. [Member] | Rate addition to London interbank offered rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Line of credit facility, basis spread on variable rate		1.00%
$3.5 billion credit facility | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount				0
Line of credit facility, amount outstanding				1,310,000,000
Swing Line Advances [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 150,000,000
Letter of credit [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		1,125,000,000
Commercial paper [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 3,000,000,000
Dec 2015, Mar & Jun 2016 [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Maximum ratio of debt to EBITDA	5.75
Sep & Dec 2016 [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Maximum ratio of debt to EBITDA	5.5
Mar 2017 & Subsequent Quarters [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Maximum ratio of debt to EBITDA	5.0
Debt to EBITDA, after acquisitions, ratio	5.5
5.95% senior unsecured notes due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt				185,000,000	185,000,000
6.05% senior unsecured notes due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt				250,000,000	250,000,000
7% senior unsecured notes due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt				175,000,000	175,000,000
7.125% unsecured debentures due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt				$ 85,000,000	$ 85,000,000